1. Field of the Invention
The present invention relates a wheel bracket mechanism for an electric wheelchair, and more particularly to a wheel bracket mechanism for an electric wheelchair equipped with auxiliary wheels.
2. Description of the Prior Arts
Electric wheelchairs have become an indispensable means of transport for the ailing old or the handicapped people to help them in indoor and out activities, such as traveling and boarding on the airplane, and so on.
A wheel bracket mechanism of a conventional electric wheelchair (and transport means or the like) is normally rectangular-formed as shown in FIG. 1, which discloses a rectangular frame 10 is provided with front wheel bracket 11 and rear wheel bracket 12 respectively at the front end and the rear end thereof for being mounted with front wheel and rear wheel respectively, and a drive wheel bracket 13 (the drive wheel bracket 13 is mounted with drive wheel) is disposed between the front and the rear wheel brackets 11,12. Furthermore, the front wheel bracket 11 and the drive wheel bracket 13 is respectively provided with a compressive spring 14, the compressive spring 14 is provided for allowing the front wheel bracket 11 and the drive wheel bracket 13 to extend or contract relative to each other upon a bump, such give rise to a cushioning effect in case of riding up and down a slope or on the uneven roads. Although this conventional wheel chair has the main functions of a wheelchair, there are still some disadvantages needs to be overcome as stability, safety and comfortableness are concerned:
First, in terms of stability, the conventional rectangular frame 10 just takes advantage of the longitudinal expansion and compression of the compressive spring 14 to maintain the stability. Although the elastic forces of the compressive spring can force the front wheel bracket 11 and the drive wheel bracket 13 to move back to the predetermined position, it may also cause vertical vibrations of the rectangular frame 10. Such an unstable electric wheelchair is not able to provide a comfortable driving to the occupants, especially to the old patients, most of them are old and disabled.
Second, in terms of security, although the conventional rectangular frame 10 is allowed to expand or contract with the help of the compressive spring 14. However, the contraction or expansion of the front wheel bracket 11 and the drive wheel bracket 13 are performed independently and individually due to no coordinating device disposed therebetween, furthermore the rear wheel bracket 12 is incompressible, Thereby the conventional rectangular frame 10 will be tilted and swayed along with the motion of the respective wheel brackets, and the center of gravity of the wheelchair moves back and forth substantially. Such that the wheelchair is susceptible to tip, it is absolutely unfit for the old and handicapped people.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional electric wheelchair.